The present application is directed to a system and method for generating a balanced LED light source, such as white light source. More specifically, embodiments of the present invention provide a high-brightness and white-balanced light source using individual red, green, and blue (RGB) LED emitters. For example, the LED light sources according to the present invention can be used for a variety of applications such as laboratory test equipment lighting, project display lighting, and others. In various embodiments of the present invention, LED light sources have been processed by optical components. In a specific embodiment, an LED light is formed by combining two or more color LEDs, and can be operated in continuous, pulsed, and/or modulated mode. There are other applications and implementations as well, as explained below.
Since the days of Thomas Edison, electrically powered lighting system has been an important application in daily life. The idea of incandescent light is still used today. For example, halogen lights is a type of popular incandescent lights used today. Another type of popular lighting method involves arc lamp in which light is produced by an electric arc.
While both halogen lamps and arc lamps are used for conventional lightings, they are often inadequate for specific applications. For example, arc lamps or incandescent halogen lamps are not among the best choice for illuminating samples in laboratory testing. Both arc lamp and halogen lamp cannot be quickly turned on and off, due to significant warm-up and cool-down periods. In addition, these types of lamp often post the risk of electrode damage in some cases. Moreover, these conventional lamps have relatively short life times.
Lasers are another type of light source that can be used. However, laser light sources usually provide narrow and collimated beams and laser light often has speckling artifacts which are not suitable for certain applications. Additionally, laser light sources are relatively expensive.
In contrast to arc lamps and incandescent halogen lamps, light emitting diode (LED) lights can be turned on and off in a very short time. With advent of this technological breakthrough, the potential brightness level of LED is increasing every day. The efficiency of LED light can be similar to traditional light sources, but often more efficient.
The advantages of using LED as light source include, but are not limited, (1) no IR or UV from LED lights (due to its narrow bandwidth); (2) no moving parts in the system, (3) instant On/Off, (4) small size, (5) low weight, (6) long Life (over 20,000 hours), (7) low voltage, (8) no mercury, and (9) unlikely to cause explosions. Therefore, the design and adaptation of LED illumination systems can be much simpler and less expensive but offer advanced performance with more functions.
For a LED light to be useful in certain applications, such as lighting samples in a laboratory, the LED light needs to emit light that has proper white-balance. For example, a sample might not be viewed correctly if the LED light casts an artificial color onto the sample. Thus, various conventional techniques have been proposed, but they are often inadequate. In many precision instruments where light output or brightness (Lumens) within limited area and working angle (collectively called Etendue) is required, the requirement on extracting and collimating as well as equalizing light from the LED emitters becomes extremely critical.
Therefore, an improved system and method for generating white balanced LED light source is desired.